In vitro

World J Microbiol Biotechnol. 2016;32(4):60

Commercially, probiotics have gained importance because of their therapeutic potential in the recent couple of decades. Several bacterial genera are used in probiotic preparations, viz; Lactobacillus, Bifidobacterium, Enterococcus, Bacillus and Streptococcus. However, accurate representation of the same, meant for both human and animal, on the labels of such dietary supplements and foods is lacking in most of the cases. Various study findings have also substantiated that large percentage of products do not contain the specified organisms, contain other species of organisms or do not contain the stated numbers of organisms.

Across the world, although a reasonable number of well-characterized probiotic strains are commercially available, search for novel strains with better potency and characteristics is on-going. Additionally, strains expressing unique and particular characteristics are of great interest, which may enable health benefits with specific functional properties.

Hence, in 2006, an expert panel proposed by FAO/WHO on selective criterion for the search of probiotic strains suggested that the probiotic activity is more important than the source of the microorganism.

Objective:

Note: Identity and genetic consistency has been covered elsewhere, hence, this section only covers evaluation of probiotic potential of LactoSpore®in vitro.

Study Design:

Resistance to Gastric Acid: The survival of LactoSpore® was examined using sterile phosphate-buffered saline (PBS) at different pH and time points

Bile Tolerance Test: The minimal inhibitory concentration (MIC) of bile for LactoSpore® was determined by examining the spots visually

Antimicrobial Activity against Human Pathogens: Antimicrobial activity of LactoSpore® was determined by well diffusion assay, wherein zone of inhibition against various pathogens was measured

Production of Lactic Acid: The test involved evaluation of lactic content and optical rotation of lactic acid produced by LactoSpore® using Polarimetric method

Results and Discussion:

Up to 4 h of the study, there was no significant difference in spore count between pH 3.0 to pH 8.0 compared to the initial spore count (Fig. 1). Hence, it was confirmed that LactoSpore® was stable in acidic as well as alkaline pH conditions

LactoSpore® was found to be tolerant against ox bile salt (1% w/v) in agar media (Fig. 2). Additionally, bile tolerance assay also demonstrated that there was no significant difference in the viability of LactoSpore® in the presence or absence of bile salt

LactoSpore® showed a broad-spectrum antibacterial activity against a panel of Gram-positive and Gram-negative human pathogens

Test on lactic acid confirmed that LactoSpore® produced 99% of L(+)-form of lactic acid and 1% of D-form. Polarimetric method also revealed that L-form of lactic acid was exclusively produced by LactoSpore®